Internet search engines algorithmically search for web documents, such as web page, weblogs (“blogs”), social media posts, images, videos, and various other documents types that are uploaded to the Internet. Typically, a user enters a search query, which could be a particular word or phrase, and in response the search engine will generate and present a listing of web documents to the user, which have been identified by the search engine as bearing some connection or relevance to the entered search query. The various search results are ranked by the search engine according to relevance, and then displayed in a list in order of decreasing relevance. The most relevant documents are situated at the top of the search results. Less relevant documents follow in order. In some cases, a position at the top of the search results for a particular search query may be guaranteed by, essentially, purchasing that privilege from the proprietor of the search engine (referred to as a “sponsored search result”). Otherwise the search ranking of a given web page for a particular search query is determined according to the search algorithm executed by the search engine.
Internet search engines typically do not search the Internet directly. Instead the search engine will “crawl” the Internet ahead of time and index every web page it encounters according to content. To perform the indexing, the search engine extracts and analyzes content taken from different locations within the web page, for example keywords included in the titles, headings, and meta tags of the web page. The extracted web page data is stored (referred to as “caching”) in the index database for later search queries in the search engine. Some search engines cache all or part of the source web page, as well as well as other potentially relevant information about the web page. Other search engines cache every word of every web page that is crawled. Accordingly, when the user enters the search query into the search engine, typically in the form of a keyword or keyword phase (though other more advanced search delimiters can be made available as well), the search engine will access the index database directly to generate a list of best-matching web pages for the particular search query.
How the search engine ranks web pages for a given search query is based on a proprietary algorithm executed in the search engine to quantify relevance. Given the sheer number of different web pages on the Internet that may include the same particular word or phase, some web pages are bound to be more relevant, popular, useful, authoritative, etc., than other web pages. The search rank algorithm makes a reasoned determination of that relevance. In a sense, therefore, the effectiveness of the search engine depends on its ability to parse through the volume to generate relevant search results for the user. Different search engines can apply different ranking algorithms based upon different parameters and weighting factors, but almost all search engines withhold specific details about their proprietary ranking algorithm to safeguard its efficacy. Should the details of the algorithms become widely known, web pages could then be cultivated to maximize their rankings in the various ranking algorithms for a particular search query without regard to the actual relevance of the web pages. Most search engines also, for this reason, constantly update and make changes to their ranking algorithms. The algorithms also evolve over time in response to changes in Internet usage and other external factors as new web techniques emerge.